(Abnormal) bullet depth seating variation...Help appreicated

[Rmeju]

So, aside from the normal few thousandths variation, I've been having some trouble with my seating depth consistancy. I must've spent an hour dinking with my press before I figured out that my test round (1 round in the progressive at a time) was achieving a seating depth .007-.009" more than my "production" rounds were getting (i.e. all 5 stations having rounds in them). So I'd set the die, I'd be right on the money, and then when I ran production, I'd be several thousandths longer than I normally see through regular variation. I even tried a different seating die of the same caliber. No help.

I cannot possibly fathom why the seating depth would change because of how many rounds are in the shellplate. Here's what I'm using:

Hornady LNL AP
Lee 4 die set w/ crimp die + RCBS lockout die
Loading 45 ACP using 230gr FMJ roundnose. Trying to seat to 1.260"

I've loaded thousands of other rounds, mostly 45 JHP and 45 LSWC and never had this problem. I have never loaded 230 gr. roundnose hardball on this press before, though. I wondered maybe if my brass was long and it was reaching the top of some of the other dies (maybe the resizer?), and thus preventing the ram from travelling its last few thousandths, and leaving the bullet seated a little long. It seems plausable, since I wouldn't notice a difference in any other operation if that's what it was. Does that happen? Am I crazy. Am I being too picky about my variation?

Thank you in advance to all those who are much smarter than me at all this!

Rmeju

 

[nicholst55]

I have zero experience with the Hornady. A Dillon 550 will show variations if adjusted with only one round in the shell plate at a time. The other 3 rounds are necessary to place an even load on the press and take up all of the 'spring' in the shell plate. You might try it and see if it makes a difference.

 

[Rmeju]

Seems plausible?

Anyone else?

 

[Walkalong]

The first round seated on my Projector will seat deeper than the next rounds because there is no round being crimped. The crimp die "stretches" things a tad as it crimps. It usually makes .002 to .005 difference. After every station is full everything stays the same. I do not size while I am loading, so there is no sizer affecting things.

Even then a +/- .001 to .003 difference in O.A.L. is pretty normal.

 

[Wilburt]

I have noticed the same thing in my LNL. I just look past it and try too load with all stations full.

I do not size while I am loading

Why? is there a benefit to this. Seems like an extra step.

 

[Rmeju]

The first round seated on my Projector will seat deeper than the next rounds because there is no round being crimped. The crimp die "stretches" things a tad as it crimps. It usually makes .002 to .005 difference.

That would explain why I don't have a problem with my lead rounds, but am having a problem with my hardball, since i don't use the FCD with my lead.

Thanks

Rmeju

 

[Walkalong]

I do not size while I am loading

Why? is there a benefit to this. Seems like an extra step

The sizing is a big force, and can affect things, but mainly it just makes loading easier and smoother without the sizing going on at the same time.

I tumble my fired brass, then I run it all through the Projector sizing and decapping. Then I hand prime with my RCBS tool, then I run them all through, expanding, dropping powder, seating the bullet, and crimping.

No sizing, and especially no priming, makes things much smoother, and you can feel little differences in expanding, seating, and crimping that would otherwise be lost in the shuffle.

Is my way better? For me? Yea. For others, I don't know.

 

[Wilburt]

Yeh I do see your point. Probally is smoother. Not sure i'm dedicated enough yet.

 

[fineredmist]

The press is designed to operate with all stations in use and it will adjust properly when used that way. Make your adjustments as you load the rounds, any that are too long or too short you set aside,pull apart and redo. It sometimes takes a little time to get it where you want but it is worth the effort.

 

[TimRB]

Make sure everything is clean, especially your seating die, shell holder, and whatever you're using to measure seating depth.

Tim